Critical Rendering Path

• HTTP
  • DNS lookup
  • TLS negotiation
  • Content download
• Rendering
  • Parse HTML into DOM
  • Stylesheets block
  • Create render tree

How to not block render

• Link tag “media” attribute to mark stylesheets as not needed
• Stylesheets in the head so the browser can progressively render content (how does it know that’s all the styles?)
• JS at end of page asynchronously